System and method for alleviating freezing gait and gait hypokinesia in users with extrapyramidal disorder

ABSTRACT

An apparatus and a method for a walking aid are disclosed. The walking aid includes a walker having a frame configured to extend about a user of the walker to at least partially support the user and to facilitate the user progressing along a path from a current step to a next step while at least partially supported by the walker. A swivel mount is supported by the frame. A light source is connected to the swivel mount. The light source is configured to project a visual cue on a projection surface in the path between the current step and the next step to trigger the next step by the user. A controller is configured to adjust a visual property of the visual cue for use under indoor conditions and outdoor conditions.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application represents the national stage entry of PCTInternational Application No. PCT/US2011/032051 filed Apr. 12, 2011,which claims the benefit of U.S. Provisional Patent Application Ser. No.61/323,232, filed on Apr. 12, 2010, both of which are incorporatedherein by reference in their entirety for all purposes.

FIELD OF THE INVENTION

The present invention generally relates to generating a visual cue for auser of a walker, or walking aid device. One aspect of the invention isto provide a constant or recurring stimulus to reduce or substantiallyeliminate the occurrence of “Freezing of Gait” (FOG), gait hypokinesia,or stride reduction in a user, such as one suffering from parkinsonism.

BACKGROUND OF THE INVENTION

Parkinsonism is a debilitating syndrome, encompassing severalneurological diseases that compromise the motor skills of its victims.Such diseases include Parkinson's Disease, vascular Parkinsonism, NormalPressure Hydrocephalus (NPH), multiple systems atrophy (MSA),progressive supranuclear palsy (PSP), and others. Globally, Parkinsonismand other such diseases are referred to as extrapyramidal disorders. Asparkinsonism progresses, one particularly debilitating problem is“Freezing of Gait” (FOG), in which an individual locks up or becomes sofixated they are unable to move or initiate further stepping movementsby their own volition. In some cases the individual feels “stuck to thefloor” as if by a magnetic force. Unfortunately, FOG is not responsiveto available medications. As a result, FOG poses a significant risk ofinjury to individuals if they are left unattended, even when trying toperform the most mundane tasks, and especially when they are in publicsettings, such as trying to cross a street. Accordingly, individualssuffering from FOG require constant monitoring and assistance.

A related problem which often occurs concomitantly in patients with FOGis gait hypokinesia. Gait hypokinesia entails patients taking with FOGis gait hypokinesia. Gait hypokinesia entails patients takingincreasingly smaller steps. In a similar fashion to FOG, gaithypokinesia is often refractory to medications. A result can be thatpatients ambulate so slowly that they become discouraged and mayincreasingly opt to use a wheelchair or motorized scooter. However, bybeing able to walk, patients can prevent muscle atrophy, maintaincardiovascular health and bone density, and preserve a positivepsychological outlook. Moderate exercise, or walking, has also beenshown to correlate with a decreased likelihood of developing cognitiveimpairment such as Alzheimer's disease.

The incidence of Parkinson's disease is reported as 1% of the populationover the age of 50, and 1.5% over the age of 65, with some occurrence inyounger individuals but negligible incidence in children. Over half amillion people in the United States are afflicted with this condition.Parkinsonism has an even broader impact with an occurrence of 30% overage 75 (where vascular Parkinsonism as the most common) and at ages over85, more than 50% suffer some form of Parkinsonism.

People have attempted to manage these FOG episodes in various ways. Themanagement techniques usually involve playing a “trick” on the brain.One technique that some use is to march or rock to sound cues such asmarching music or counting. Another method is to provide some visual cuethat encourages the feet to step up and over, as if unsticking fromglue, rather than stepping forward, as with regular walking. Thesetricks are usually taught in the physician's office by the doctors,nurses, and therapists who are familiar with the symptoms. People alsolearn the methods from reading books about Parkinson's disease or byattending support group meetings. Because actual visual cues are oftenimpractical outside of a controlled and prepared environment, such as atherapist's office, some are taught to draw an imaginary line in frontof the afflicted person's feet and encourage him or her to “step up andover the imaginary line.” Also used is the dropping or placing ofobjects on the floor in front of the person's feet; forcing them to stepover the object (paper, tissue, straws, belts, and the like). Virtuallyany object can be used to “step up and over.” A number of these methodsare disclosed in U.S. Pat. Nos. 5,575,294; 6,330,888; US 2004/0144411;US 2006/0292533; and US 2007/0255186.

FIG. 1 is an illustration of an example prior art system 10 forprojecting a visual cue to alleviate FOG in an individual such as thatdescribed in U.S. Patent Publication No. 2006/0025836, herebyincorporated by reference. The device includes a battery pack or powersource 20 that is connected to light source 15. Light source 15 isconfigured to project a visual shape or pattern. System 10 includes clip25 for attaching light source 15 to a user or object. Generally, clip 25is configured to attach to an article of the user's clothing, such as abelt, shoe, or waistband such that light source 15 directs the visualshape or pattern on the ground ahead of the user while the user walks.

Prior art projection systems such as that shown in FIG. 1 have severaldisadvantages. First, when attached to an article of the user'sclothing, the position of light source changes as the user moves.Because the light source can shift around, at the time a user isaffected by FOG, it is extremely unlikely that the light source will becorrectly oriented to assist the user. Similarly, if the user is shakingor trembling, the light source will be affected by those movements,resulting in the visual pattern shaking violently over whatever surfacethe light source is oriented towards. Furthermore, because the patternis projected some distance away from the light source, even the smallestmovement of the user is magnified making the device extremely difficultto use.

Although the prior art systems may be attached to surfaces or objectsthat are relatively more stable, such as a cane, or walker, in order toprovide a connection sufficient to fix the light source to the objectsafely, any such clip or attachment device must be extremely strong.Such a clip could be extremely difficult for an elderly person, or aperson suffering from Parkinsonism or similar disease, to operate. As aresult, conventional project systems such as that illustrated in FIG. 1are of little benefit to a user suffering from FOG and gait hypokinesia.Furthermore, in many prior art devices the visual cue is directed anunhelpful position within the user's stride. Some devices, for example,generate a visual line that cannot be moved and projects onto a walkingsurface at approximately the level of a patient's heels.

The aforementioned systems have been helpful to people, but each hasdrawbacks. Sound cues (such as marching music) are not often feasible,particularly outside the home, and many find singing or counting aloudembarrassing. Dropping or placing items on the floor requires not onlythat you have the objects ready to use but that someone be available toplace and retrieve the objects. One alternative to this is to use smalldisposable objects, such as cards, and leave the object(s) behind. Withother objects, if the object is 3-dimensional, such as a belt, theindividual could trip and fall. The imaginary line method works well,but again, someone usually must accompany the individual to draw theline with their foot or hand. Some patients find it difficult to imaginea line during the freezing episode and remain unable to move untilinvoluntary release occurs.

The visual stimulations proposed also do not meet all of the needs ofthe user. The visual images are not adjustable in that they do not turnin the direction of the user's motion. Also, the challenges of differentlight conditions between indoors and outdoors are not addressed. Often,a Parkinsonian patient will just sit down and stop what he or she isdoing. At the present time, these homemade tricks or clip-on devices arethe only mechanical techniques available to individuals in the UnitedStates who suffer from freezing and gait hypokinesia. For many people,the above-listed techniques are too impractical to consider usingconsistently. Thus, there is a need for a system to assist sufferers ofFOG, and gait hypokinesia that does not contain the above drawbacks.

SUMMARY OF THE INVENTION

The present invention is directed generally to a device and method foralleviating freezing of gait in a user, such as one suffering fromparkinsonism or other extrapyramidal disorder. The device includes alight source, for example, a laser or LED, adjustably seated in aholder. The light source is focused into a visual cue. As the user stepstoward the visual cue, the visual cue advances with the user, to createa continuing, successive stimulus for eliminating freezing for eachstep. If the user attempts to turn in a given direction, the device mayactuate in such a way as to maintain the visual cue in front of theuser.

In one implementation, the present invention includes a walking aid. Thewalking aid comprises a walker having a frame configured to extend abouta user of the walker to at least partially support the user and tofacilitate the user progressing along a path from a current step to anext step while at least partially supported by the walker, a swivelmount supported by the frame, and a light source connected to the swivelmount. The light source is configured to project a visual cue on aprojection surface in the path between the current step and the nextstep to trigger the next step by the user. The walking aid furtherincludes a controller configured to adjust a visual property of thevisual cue for use under indoor conditions and outdoor conditions.

In other implementations, the present invention includes a walking aid.The walking aid comprises a walker having a frame configured to extendabout a user of the walker to at least partially support the user and tofacilitate the user progressing along a path from a current step to anext step while at least partially supported by the walker, and a lightsource connected to the frame and configured to project a visual cue ona projection surface in the path between the current step and the nextstep to trigger the next step by the user. The walking aid includes aprocessor connected to the frame and configured to determine an intendedwalking path of a user of the walker, the intended walking pathdeviating from the path, and position the visual cue in the intendedwalking path of the user.

In other implementations, the present invention includes a method ofalleviating freezing of gait in a user of a walking aid. The methodcomprises detecting a differential weight input at a frame of thewalking aid. The walking aid is configured to extend about a user to atleast partially support the user and to facilitate the user progressingalong a path from a current step to a next step while at least partiallysupported by the walking aid. The method includes using the differentialweight input to determine a projected path of the user, and projecting avisual cue in the intended walking path of the user using a light sourceconfigured to project a visual cue on a projection surface in the pathbetween the current step and the next step to trigger the next step bythe user.

Other aspects and features of the present invention will become apparentin view of the figures and the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts an example prior-art device comprising a light sourceconnected to a clip for mounting the light source.

FIG. 2 is an illustration of the exemplary device of the presentinvention.

FIGS. 3A and 3B illustrate the exemplary device according to the presentinvention, after being angularly adjusted to match a user-initiatedturn.

FIG. 4 is a diagram of the interrelated functional components of awalking aid that can be used to alleviate symptoms of, for example, FOG.

FIG. 5 is a flowchart illustrating a method for detecting that a user ofthe present system is initiating a turn.

FIG. 6 is an illustration of an alternative implementation of thepresent walking aid device.

DETAILED DESCRIPTION OF THE INVENTION

The present disclosure is directed to a device and method that may beused to alleviate “Freezing of Gait” (FOG) in a user suffering fromparkinsonism or a similar neurological disorder. The device may also beused as a gait rehabilitation therapy to encourage a user suffering fromgait hypokinesia that has decreased stride length to lengthen theirstride. It has been known that some users of walkers may make suddenmovements or leave their walker behind when rushing to make a turn.Therefore, the device may also be used to facilitate proper walker, orother walking aid, usage by encouraging the user to keep the walkerproperly situated in front of them in their direction of motion. Properwalker usage may also be improved with appropriate posture, which thepresent device can help to improve by encouraging a user to place theirfeet at an appropriate location beneath a walker. The device can also beused for fall prevention in that a user is encouraged to concentrateupon stepping in the appropriate places as directed by the light source,and therefore less likely to slip or inadvertently lose their footing.

The device and method of the present invention provide a visual cue tothe user to cause or trigger an autonomic response. In one aspect, thevisual clue is a line or other pattern projected onto a projectionsurface (e.g., a ground surface) orthogonal to the direction of motionof the user, typically on the floor or ground. The line may also beturned such that it is no longer lateral to the sides of the walker orwalking aid, but is instead orthogonal to the newly intended directionof motion upon entering a turn. It has been found that such a line cantrigger a response in parkinsonism sufferers to step on or across thevisual cue, thereby eliminating the freezing for at least that step.Successive visual cues can be created as the user moves forward. Thedevice and method of the present invention, therefore, use a visual cueto alleviate FOG. Although various examples of the present system andmethod are described in the present disclosure as alleviating FOG in anindividual, it is to be understand that the present system may begenerally used to alleviate FOG in addition to stride reduction or gaithypokinesia in an individual. As such, in the following discussion,references to FOG should be understood to apply equally to stridereduction and gait hypokinesia.

With this visual cue, fall prevention may also be facilitated by leaningforward to step on or over the visual cue. The user may be less prone tofalls from auto-retropulsion a result of impaired postural reflexeswhich commonly affect patients with Parkinsonism.

FIG. 2 depicts an embodiment of the present walker 100. Light source 102is configured to project visual cue 104. Visual cue 104 is configured tospread out on the floor, ground surface, or another projection surface106, ahead of or behind the front feet or wheels of walker 100 havingfront legs 100 a and in the walking path of the user (indicated by arrow126). Visual cue 104 may include a single solid projection, or severalseparate projections, such as projections 116 shown in FIG. 2. Althougha single, solid projection may facilitate viewing, for battery savingpurposes, a broken, or dashed visual cue 104 can be used.

Visual cue 104 is configured to move either forward or backward (e.g.,from position 104 to position 104′) by a distance 114 in such a way asto accommodate the preference of the walker's user, or to facilitate aparticular treatment. That is, for fall prevention, for example, visualcue 104 can be positioned to be directed over a user's feet such thatthe user concentrates on where their feet have been or will be located.With gait training for example, the visual cue can be projected outahead of the user to provide the user with a goal to lengthen the user'sstride in order to reach the visual cue.

In some cases, walker 100 includes a controller (e.g., implemented bymicroprocessor 50 of FIG. 4) that automatically accommodates the user'sstride length by monitoring a movement of walker 100 to characterize thestride length of the user. Then, based upon the determined stridelength, the controller can select an appropriate position for the visualcue 104, for example by moving the visual cue from position 104 toposition 104′ as shown in FIG. 2, or to accommodate any other stridelength appropriate for the user.

In one implementation, walker 100 includes a system such as an inertialmeasurement unit or system, or global position system (GPS) connected tothe controller to detect movement (including both velocity and distance)of walker 100. Alternatively, in walkers that include wheels 108 (suchas walker 100 illustrated in FIG. 2), walker 100 movement is detectedusing one or more wheel sensor 110 connected to either, or both, wheels108. After collecting some movement data from walker 100 using any ofthe above measurement systems (either individually or in combination),the controller can than analyze the movement data to identify distancesover which walker 100 is characterized by constant movement, followed bypauses, indicating that the user has taken a step. This information canbe used to determine the stride length of the user, which can then beused to identify an appropriate positioning of visual cue 104 to achievethe optimum performance of walker 100, either by assisting the user incontrolling stride length, or to direct visual cue 104 over the user'sfeet to assist in fall prevention, for example. After determining thestride length of the user, the controller moves visual cue 104 by anappropriate distance 114 to position visual cue 104 in the optimumlocation.

A bracket and clamp arrangement may secure light source 102 to walker100. In the implementation shown in FIG. 2, light source 102 is coupledto walker 100 using universal swivel mount 112 that connects the lightsource to a mounting bracket allowing the light source to pivot. Swivelmount 112 may include a universal joint, such as a cardan joint,hardy-spicer joint, or hooke's joint. Alternatively, swivel 112 mayinclude a ball and socket joint to allow for free movement of lightsource 102. As described below, a motor or other actuator may be coupledto swivel 112 for adjusting a position and orientation of light source102.

The light source may be powered by any suitable energy source, forexample, one or more batteries. Any size battery may be used as neededto supply sufficient power to the light source. Additionally, thebattery or batteries may be rechargeable. Rechargeable batteries alsomay be used to stabilize voltage or current of the power source. Ifdesired, a pressure sensitive ceramic, an electromechanical generatingdevice, or a similar medium may be used to produce the necessary powerfor the light source. The power source may be enclosed in a housing orpack which may include a band, clip, or other fastener to secure thehousing to a belt, walker, coat pocket, or the like.

In one implementation, energy source 118 is mounted within the frame ofwalker 100 and connected to light source 102. With the energy sourcemounted within the walker, the user of walker 100 is not required tocarry a power source separately. As shown in FIG. 2, in oneimplementation, energy source 118 is mounted within a cross bar ofwalker 100. This configuration ensures a lateral weight balance betweenthe left side and the right side of walker 100. By maintaining anevenly-balanced weight distribution, there is less danger that walker100 will tip, particular when lifted by a user. In otherimplementations, however, the energy source may be mounted within walker100 at any suitable location, even if to one side of walker 100, forexample by being disposed within one leg of walker, or outside of thewalker.

The light source may be a laser source (e.g., a type 3A, 635 nanometerlaser (Laserex Model LDM-4-635-3-L30) emitting a red light configured ina line at three milliwatts, with the line being projected at a distanceof 90 centimeters (cm) from the line's origin, with the line having alength of approximately 60 cm), such as a YAG or helium-neon laser,capable of high intensity, or a Krypton bulb source. The opticalelement(s) of the system may consist of any suitable combination ofprisms, gratings, grisms, or collimators (see, for example opticalelement 120) that creates the desired pattern from the laser beam. Orthe optical elements may be limited to a simple cast or molded shapedglass or plastic article having a shape that internally reflects lightand serves as a beam-shaping waveguide body that spreads the round beaminto a strip-like curtain and projects it as a collimated rectangularbeam, so that no further optical elements are required for focus orshape adjustment. Another possibility is for an individual LED or groupof LEDs to be used. However other optics, different patterns orpattern-defining elements, and other light sources may be used as well.

Light source 102 may also include a color which is easily discernable inboth outdoor and indoor conditions or changeable for various lightingconditions. For example, in some circumstances, a green laser (e.g.,having a wavelength of approximately 495-570 nanometers) shows up muchmore readily in outdoor day light, but can be overly bright for indoorconditions where a red laser (e.g., having a wavelength of approximately620-750 nanometers) can be more efficacious. The light source cantherefore be modifiable to contain a dual red/green laser system wherethe user can specify which they would like to use, or the device canautomatically select which is appropriate based upon light conditionsusing a controller such as processor 50 (for automatic selection) or amanual switch such as switch 122 shown on FIG. 2). This same concept canbe extended to LED or other light sources. In some implementations, thewalker includes a light sensor (see, for example, sensor 136 of FIG. 2)to detect a level of ambient light. Based upon the light level (and, infact, the spectrum of ambient light), the walker may be configured toselect the most appropriate output light color for the light source. If,for example, the light sensor detects a high level of ambient light, amore intense, bright output color may be output by the light source at ahigher power level. Conversely, in low ambient light conditions, thewalker may select a different, more appropriate, color and output thelight using less power.

A separate switch button 122 is positioned for ease of activation toturn the light source on and off. This switch may include a heatactivated switch, a pressure activated switch, a timer switch, or someother form of tactile switch. Light emitting diode (LED) 124 may beprovided to indicate whether the device is powered on. In one aspect, apulsed LED is used to conserve power and increase battery life. Switch122 can be a push button switch, and a set of rechargeable batteriesfrom within the device provides the power supply. A timer connected to,for example, switch 122 of FIG. 2 may be configured so that, once theswitch is pressed, the unit stays lit for a fixed short time interval,for example, two, five or ten seconds. Alternatively, the device may beprovided with a motion or other sensor (not shown) that automaticallyturns the device off after a period of inactivity. Likewise, the devicemay be provided with a sensor that automatically turns the device onwhen motion is detected, for example using wheel sensors 110. In somesuch aspects, the sensor further may be adapted to detect motion in adesired direction or at a minimum height, such as detecting a forwardmotion or movement of the user using wheel sensors 110, so that motioncaused by shaking of the user would not necessarily activate the device.A control may be included that blinks the power on and off during theactuation period. This may be useful either for charging a high powerstorage device to fire a strobe light (e.g., xenon flash source) toobtain higher intensity, in which case the unit serves to adapt a lowvoltage power source to a high intensity light source, or the source mayblink simply to make the projected light pattern 104 more visuallynoticeable to enhance its effectiveness for overcoming a freezingincident.

Numerous mounting positions for light source 102 are possible on thebody of the walker 100, and different forms of articulation or bracketsmay provide flexibility in aiming the device. Depending on the form ofillumination employed, light source 102 may be mounted as shown in FIG.2 on a front cross member, at a position low to the ground, to maximizethe intensity of the projected image, or higher up on a side bracket orcross-piece or on a seat mounted to the walker. In embodiments where theprojector is built into a leg or in a cross bar, it may have internalwiring to button 122 to allow a user to control the operation of lightsource 102. Alternatively button 122 may function wirelessly in order tobe located at a more easily reached position for activating theprojection controls for light source 102. Whether light source 102 isintegral or added on, the frame of the walker 100 generally provides afixed reference that allows light source 102 to be precisely and, insome cases, permanently aimed and focused on a ground surface in thecorrect position. In a walker with roller wheels, the activator buttoncan be mounted adjacent to one of the hand brake control levers.

FIGS. 3A and 3B show alternative implementations of the device, whereinwalker 101 is configured to direct visual cue 104 to different positionson a projection surface 106 (e.g., the ground) to assist a user inmaking a turn with walker 101. By adjusting the position of visual cue104 on the ground or projection surface, the device can prompt a user totake a step where the stepping foot does not move along the user'sprevious walking path and, instead, is placed to one side of the walkingpath. For example, by moving visual cue 104 away from the walking path,a user can be prompted to take a step where the foot is place to oneside of the walking path, thereby initiating a turn. By maintainingvisual cue 104 in a displaced position, after taking a number of steps,the user can complete the desired turn.

FIG. 3A depicts the light source 102 and visual cue 104 as the userinitiates a right-hand turn (from the user's perspective) away fromwalking path 126 towards the turned walking path 128. As the userinitiates a turn, light source 102 and visual cue 104 are rotated byrotation of light source 102 (e.g., by movement of universal bracket 112of FIG. 1) through a predetermined arc in such a way as to aid the userin maintaining concentration on the visual cue. In one such embodiment,visual cue 104 may be represented by a line (or broken line) which iskept fixed at its right end as a pivot point, and the rest of the lineis rotated clockwise around the right end. The pivot point could bechanged; for example it could be in the middle of visual cue 104 orvisual cue 104 could be rotated in some other fashion and this exampleis not intended to be limiting in any way. If the cue had remainedstationary, the user may not have maintained concentration on the visualcue, or may not have received a benefit from the cue at all, and wouldtherefore have suffered from FOG or another of the detriments that thedevice is designed to treat.

FIG. 3B depicts another embodiment of how the visual cue 104 could bemoved while the user initiates a right-hand turn. In this embodiment,the visual cue is not rotated but is offset or translated in such a wayas to move the cue to the right (in the direction of the turn 128) andaway from the user's original path 126 (though it could also be movedtowards the user if so desired). In the example shown in FIG. 3B, thetranslation can be achieved by a mechanism that moves light source 102back and forth along the cross bar 130 of walker 101.

In both of the above embodiments depicted in FIGS. 3A and 3B, theuniversal swivel (see, for example, element 112 of FIG. 2) is actuatedin such a way as to move the light source in order to rotate or movevisual cue 104 into a displaced position along the new direction oftravel when a user makes a turn. This can be accomplished in a number ofpossible ways. One way is for gyroscopes to be attached either to thedevice or the walker which will indicate when the direction of travel ischanging, and will control the swivel either directly or through acomputer processing means to move the visual cue. Another possibility isfor pressure sensors to be mounted in the feet, legs, or handles of thewalker such that when a person leans on one side of the walker therebyplacing more pressure on one side of the walker's legs indicating theuser is making a turn, the swivel will move the visual cue accordingly.Depending upon the implementation, the sensors may be placed in each legof the walker, or in only two of the legs. Generally, any sensor systemthat allows for the determination of whether the user is pressing downmore heavily on one side of the walker or the other can be used inconjunction with the present system. For example, sensors may be placedin the handles of the walker to detect a weight or pressure applied tothe handles or the legs of the walker. In that case, although notmeasuring a weight or pressure applied to the legs directly, the handlesensors measure such a force indirectly.

With reference to FIG. 2, for example, pressure sensors 132 are disposedwithin each leg of walker 100. As shown in FIG. 2, pressure sensors 132may be disposed proximate the feet, or wheels of the various legs ofwalker 100 to allow for accurate readings to be taken at each pointwalker 100 contacts ground surface 106. Alternatively, weight orpressure sensors may be mounted within handles 134 of walker 100 todetect a weight applied by the hands of the user.

FIG. 4 is a block diagram illustrating the functional components of awalker configured to automatically adjust a position of the swivel tomove the light source to facilitate the turning of a user.Microprocessor 50 is mounted on or within the walker and connected topower source 52 and memory 60. Microprocessor 50 is also incommunication with sensors 54 and 56. In one implementation, sensor 54is configured to detect a weight or pressure applied to a left side ofthe walker (e.g., through a handle or leg of the walker), while sensor56 is configured to detect a weight or pressure applied to the rightside of the walker. In other implementations, though, differentcombinations of sensors may be used for detecting a weight or pressureapplied to any number of legs or handles of the walker.

Microprocessor 50 executes software that retrieves data from sensors.Using the data from sensors 54 and 56, microprocessor 50 determineswhether a user is applying more weight to either the right or left sideof the walker, or whether the walker is in balance. As such,microprocessor 50 can be configured to detect a differential weightinput to the handles of the walker. If microprocessor 50 detects moreweight to one side than another, the processor determines that the useris initiating a turn and instructs motor 58 to modify a position of thelight source (e.g., light source 102 of FIGS. 2, 3A, and 3B) to assistin such a turn. The degree to which the light source is displaced can beat least partially determined by the degree of difference in pressureapplied to one side of the walker versus the other.

FIG. 5 illustrates a method for directing the visual cue of the presentsystem using pressure sensors mounted within a walker. Although method200 is described in terms of a walker having two pressure sensors (see,for example, the block diagram of FIG. 4), with one configured to detecta weight applied to a left leg and one configured to detect a weightapplied to a right leg, method 200 may be modified to work with walkershaving other combinations of sensors.

Method 200 may be executed by a microprocessor mounted to or within awalker. In a first step 202, the microprocessor retrieves a measurementfrom a first sensor configured to detect a weight or pressure applied toone of the right legs of the walker. In step 204, the microprocessorretrieves a measurement from a second sensor configured to detect aweight or pressure applied to one of the left legs of the walker.

The processor then determines the difference between the two values instep 206. If the difference is greater than a predetermined threshold instep 208, then in step 210, the processor instructs a motor connected tothe swivel mount to move the lighting device to a corresponding,predetermined position. The differences may have positive values,indicating the user is turning in a first direction, or negative values,indicating the user is turning in a second direction. Depending uponsystem requirements, many different thresholds can be defined, wherethresholds having larger absolute values indicates sharper turns causinga greater displacement of the light source. After turning the lightsource, method 200 repeats. In some cases, extreme thresholds may bedefined that indicate the weight differential is so great that thewalker is in danger of tipping. In that case, if the weight differentialexceeds the threshold, the walker may be configured to sound an alarmvia a speaker connected to the frame of the walker to alert the user asto the possible tipping condition.

If the difference between the two sensor values does not exceed apredetermined threshold, then method 200 returns to step 202 andrepeats.

After completing a turn, the user stops applying a differential pressureto the walker and both the right leg and left leg sensor detect the samepressure (or the same pressure within a predetermined error margin). Inthat case, the microprocessor causes the motor to return the lightsource to its non-displaced position. In some cases, therefore, if theanswer to step 208 of FIG. 5 is no, the processor always causes thelight source to return to its default position.

In some implementations, the sensor system includes memory 60 (shown onFIG. 4) for storing several sensor measurements made over a period oftime such as the last 5 or 10 seconds. For example, the system may storesensor measurements every 1 second and store a maximum of 10 records. Byrecording several sensor measurements, the processor can compare themost current measurement to those made over some time to identify trendsor anomalies. This may be used to alleviate problematic measurementsresulting from a user of the walker momentarily striking or pushing downon one handle of the walker. Accordingly, the memory can be used tosmooth out measurements. In one specific implementation, during thecomparison step 208 shown in FIG. 5, before comparison, the processormay average the last 10 measurements for the left leg and the right legsensor so that the processor compares only average measurement values,not the most recent values.

In some cases a user will naturally apply a different weight to thehandles of the walker during use, even when walking in a straight line.As such, that user's normal operation, even when moving in a straightline, results in an unbalanced input at the walker's handles and,consequentially, the walker's legs. In that case, the walker may beconfigured to allow a user to establish a default position. The defaultwould allow the user to define the unbalanced input as that user'snormal, straight line input. Deviations from that input, then, could beused to identify when the user is initiating a turn and to determineappropriate positioning of the light source. The default may be storedin memory and used by the processor to compensate for a user's walkingtechnique.

Yet another possibility is for the device to track where the user islooking, and move the visual cue according to where they are looking tomove. If the user looks to the right, the visual cue will move or rotateto the right. If the user looks to the left, the visual cue will move orrotate to the left.

FIG. 6 is an illustration of an alternative implementation of thepresent walking aid. Walking aid 300 includes frame 302 configured toextend at least partially about a user and provide support to that useras he or she progresses along a walking path.

Light source 304 is connected to frame 302 of walker 300. Light source304 is configured to project visual cue 306 into the walking path of theuser, or over the feet of the user, as discussed above. As shown in FIG.6, a position of visual cue 304 can be adjusted (e.g., from the positionof visual cue 306 to the position of visual cue 306′) to assist theuser. The position may be selected to alleviate FOG, to assist inmodifying the stride length of, or to mitigate gait hypokinesia in theuser, again, as described above. As illustrated in FIG. 6, the positionof visual cue 306 may be, at least in some part, determined by a heightof the user of the walker 300.

Walker 300 includes a number of wheels 308 to facilitate movement ofwalker 300. Wheels 308 may be connected to wheel sensors, as describedabove, for monitoring a movement (e.g., speed and distance) of thewalker for determining an appropriate position of visual cue 306 for theuser. Wheels 308 are connected to braking levers 310 for controlling therotation of wheels 308. Braking levers 310 are connected to the brakesof wheels 308 via cables 312.

Referring to FIG. 6, box 6 b shows an enlarged portion of the regionindicated by box 6 a on FIG. 6. As shown in box 6 b, light source 304 isconnected to frame 302 of walker 300 via bracket 314. Bracket 314 may beconfigured in the same manner as universal swivel mount 112 of FIG. 2,for example. Alternatively, bracket 314 can include any light source 304mounting system that can be adjusted to control a position of visual cue306 on a project surface for a user. Also, as discussed above, bracket314 (or light source 304) may be connected to a motor or other actuatorfor automatically modifying a position or orientation of light source304 via a controller, such as a user interface (e.g., a switch orbutton) or via commands issued by a controller.

Light source 304 is connected to power or energy source 316 via cable318. Energy source 316 may include a control switch that is configuredto control power delivery to light source 304, or to otherwise controlan operation of light source 304, for example by causing light source304 to periodically flash, change color, modify a position of lightsource 304, or otherwise control an operation of light source 304. Inthat case, power source 314 may incorporate, or be in communication witha processor or controller (such as microprocessor 50 of FIG. 4) fordetermining an appropriate position of visual cue 306 and controlling atleast one of a position and orientation of light source 304 to positionvisual cue 306 in, or proximate to, that determined location.

In the same manner as the prior art, the device could be used inconjunction with a belt, a hat, a shoe, a cane, or the like, or placedsomewhere else on a user or a walking aid. Accordingly, it will bereadily understood by those persons skilled in the art that, in view ofthe above detailed description of the invention, the present inventionis susceptible of broad utility and application. Many adaptations of thepresent invention other than those herein described, as well as manyvariations, modifications, and equivalent arrangements will be apparentfrom or reasonably suggested by the present invention and the abovedetailed description thereof, without departing from the substance orscope of the present invention.

The invention claimed is:
 1. A walking aid, comprising: a walker havinga frame configured to extend about a user of the walker to at leastpartially support the user and to facilitate the user progressing alonga path from a current step to a next step while at least partiallysupported by the walker; a swivel mount supported by the frame; a lightsource connected to the swivel mount, the light source configured toproject a visual cue on a projection surface in the path between thecurrent step and the next step to trigger the next step by the user; acontroller configured to adjust a visual property of the visual cue foruse under indoor conditions and outdoor conditions; further comprising amotor connected to at least one of the swivel mount and the light sourceto modify at least one of a position and an orientation of the lightsource to modify a position of the visual cue on the projection surfacewith respect to the path; further comprising a first sensor connected tothe walker to detect a first pressure applied to the walker; andwherein, in response to the first pressure detected by the first sensor,the motor is configured to adjust the at least one of a position and anorientation of the light source to project the visual cue away from thepath and toward a projected path.
 2. The walking aid of claim 1, whereinthe controller is configured to receive an indication of the firstweight detected by the first sensor and, using the indication of thefirst pressure, determine the projected path implied by the firstpressure and communicate the adjustment of the at least one of aposition and an orientation of the light source to the motor to projectthe visual cue away from the path and toward the projected path.
 3. Thewalking aid of claim 1, wherein the swivel mount is configured toautomatically adjust a position of the visual cue in response todirectional changes by the user and the walking aid includes at leastone of a gyroscope, pressure sensor, and user eye tracking systemconfigured to monitor directional changes by the user.
 4. The walkingaid of claim 1, further comprising a collimator disposed around thelight source and configured to increase an intensity of the light sourceon a predetermined projection area.
 5. The walking aid of claim 1,wherein the light source is configured to generate first and secondvisual cues.
 6. The walking aid of claim 5, further comprising a lightsensor connected to the frame and configured to detect an ambient lightlevel about the walker, and wherein the controller is configured to usethe ambient light level to select one of the first visual cue and thesecond visual cue for outputting by the light source.
 7. The walking aidof claim 5, wherein the first visual cue is configured for indoor useand the second visual cue is configured for outdoor use.
 8. The walkingaid of claim 7, wherein the first visual cue consists of a light havinga wavelength between approximately 620 nanometers and approximately 750nanometers and the second visual cue consists of a light having awavelength between approximately 495 nanometers and approximately 570nanometers.
 9. A walking aid, comprising: a walker having a frameconfigured to extend about a user of the walker to at least partiallysupport the user and to facilitate the user progressing along a pathfrom a current step to a next step while at least partially supported bythe walker; a swivel mount supported by the frame; a light sourceconnected to the swivel mount, the light source configured to project avisual cue on a projection surface in the path between the current stepand the next step to trigger the next step by the user; a controllerconfigured to adjust a visual property of the visual cue for use underindoor conditions and outdoor conditions; further comprising a motorconnected to at least one of the swivel mount and the light source tomodify at least one of a position and an orientation of the light sourceto modify a position of the visual cue on the projection surface withrespect to the path; further comprising a first sensor connected to thewalker to detect a first pressure applied to the walker; furthercomprising a second sensor connected to the walker at a positiondisplaced from the first sensor to detect a second pressure applied tothe walker at the position displaced from the first sensor; wherein thecontroller is configured to receive an indication of the first pressuredetected by the first sensor and an indication of the second pressuredetected by the second sensor and determine a differential therebetweenand, using the differential, determine a projected path implied by thedifferential and communicate an adjustment of the at least one of aposition and an orientation of the light source to the motor to projectthe visual cue away from the path and toward the projected path.
 10. Thewalking aid of claim 9, wherein the controller is configured to: comparethe differential to a predetermined threshold; and when the differentialexceeds the predetermined threshold, communicate the adjustment of theat least one of a position and an orientation of the light source to themotor.
 11. A walking aid, comprising: a walker having a frame configuredto extend about a user of the walker to at least partially support theuser and to facilitate the user progressing along a path from a currentstep to a next step while at least partially supported by the walker; alight source connected to the frame and configured to project a visualcue on a projection surface in the path between the current step and thenext step to trigger the next step by the user; and a processorconnected to the frame and configured to: determine an intendeddeviation from the path of the user of the walker, and position thevisual cue in the intended deviation from the path of the user of thewalker by altering the position of the light source with respect to theframe of the walker.
 12. The walking aid of claim 11, whereindetermining the intended deviation from the path of the user includes:receiving an indication of a pressure differential applied to the frameof the walker; using the indication of the pressure differential todetermine a projected path implied by the differential; and adjusting aposition of the visual cue to position the visual cue away from the pathand toward the projected path.
 13. The walking aid of claim 11, whereinthe light source is configured to generate first and second visual cues.14. The walking aid of claim 13, further comprising a light sensorconnected to the frame and configured to detect an ambient light levelabout the walker, and wherein the processor is configured to use theambient light level to select one of the first visual cue and the secondvisual cue for outputting by the light source.
 15. A method ofalleviating freezing of gait in a user of a walking aid, comprising:detecting a differential pressure input at a frame of the walking aid,the walking aid configured to extend about a user to at least partiallysupport the user and to facilitate the user progressing along a pathfrom a current step to a next step while at least partially supported bythe walking aid, the walking aid including a light source configured toproject a visual cue on a projection surface in the path between thecurrent step and the next step to trigger the next step by the user;using the differential pressure input to determine a projected path ofthe user; and projecting a visual cue in the projected path of the userby altering the position of the light source with respect to the frameof the walking aid.
 16. The method of claim 15, wherein the light sourceis configured to generate first and second visual cues.
 17. The methodof claim 16, further comprising: detecting an ambient light level aboutthe walking aid; and using the ambient light level to select one of thefirst visual cue and the second visual cue for outputting by the lightsource.